The New Final Boss

We need a boss that is so ridiculous to defeat that only 0.1% of players will kill them, and the only loot is one guaranteed drop, a single use, cosmetic unlockable. The cosmetic will be something like a character aura, exclusive to unlocking through gameplay, and non tradable. The description of the item will have a perpetually updating stat displaying how many players have unlocked it. If the number of players that have unlocked it goes beyond 0.1%, GGG must make a next level, more difficult, uber boss with a new cosmetic unlockable for elites to obtain. With a mechanic like that we could then simply remove exp loss on dea.... well nevermind; but, that new final boss sounds epic.